Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2017	$ 83,139	$ 5	$ (8,443)	$ 288,277	$ (232)	$ (196,468)
Beginning balance (shares) at Dec. 31, 2017		55,136,038	(3,845,496)
Increase (Decrease) in Stockholders' Equity
Exercise of warrants and stock options awards	1,845			1,845
Exercise of warrants and stock options awards (shares)		856,441
Stock-based compensation expense	3,820			3,820
Common stock issued for settlement of restricted stock units net of shares withheld to satisfy income tax withholding obligations	(1,312)			(1,312)
Common stock issued for settlement of restricted stock units net of shares withheld to satisfy income tax withholding obligations (shares)		786,693
Common stock issuance in connection with employee stock purchase plan	523			523
Common stock issuance in connection with employee stock purchase plan (shares)		177,763
Treasury stock — repurchase of stock	(23,537)	$ (1)	$ (23,537)	1
Treasury stock — repurchase of stock (shares)			(8,718,744)
Net income (loss)	(9,366)					(9,366)
Foreign currency translation adjustment	(717)				(717)
Ending balance at Dec. 31, 2018	54,395	$ 4	$ (31,980)	293,154	(949)	(205,834)
Ending balance (shares) at Dec. 31, 2018		56,956,935	(12,564,240)
Increase (Decrease) in Stockholders' Equity
Exercise of warrants and stock options awards	$ 6,749			6,749
Exercise of warrants and stock options awards (shares)	1,689,161	1,693,661
Stock-based compensation expense	$ 5,759			5,759
Common stock issued for settlement of restricted stock units net of shares withheld to satisfy income tax withholding obligations	(1,391)			(1,391)
Common stock issued for settlement of restricted stock units net of shares withheld to satisfy income tax withholding obligations (shares)		692,286
Common stock issuance in connection with employee stock purchase plan	511			511
Common stock issuance in connection with employee stock purchase plan (shares)		138,175
Net income (loss)	(9,007)					(9,007)
Foreign currency translation adjustment	(238)				(238)
Ending balance at Dec. 31, 2019	$ 56,777	$ 4	$ (31,980)	$ 304,781	$ (1,187)	$ (214,841)
Ending balance (shares) at Dec. 31, 2019		59,481,057	(12,564,240)